the right shunt trip?

cadric

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May 3, 2018
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Hi there,

I still need a Shunt Trip for my Powerwall for savety.
I know that a lot of you use these ABB S5 Shunt Trips, but I don't have enough space for this items.
I have a little cabinet where I installed the DC switches between my two Inverters and the Batteries.


image_nejcbn.jpg

you can see the cabinet in the middle between the Inverters

My question now is, can I use some of these items as shunt trip?


ABB

Siemens


Or do I need to use one of this ABB S5 ones?


Regards


cadric
 

daromer

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Whats the current you want to be able to trip?

S3N is smaller as example.

The ones you linked are shunt trips for normal breakers. Can you find Breakers large enough? In generall max is 63A only.
 

Crimp Daddy

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It looks like you linked the shunt trip coil / accessory for a breaker. I believe you still need to pair that with a compatible breaker. Also make sure your control signal voltages are compatible with your system.

I am using the ABB S3B with a 200A rating.

It all comes down to your current interrupt rating... I wanted something larger for the headroom, but as my system grows, 200A will be a reasonable rating for the breakerwith 4 parallel sets of EV cells.


image_esuhan.jpg



image_eaklzf.jpg



image_jzwapk.jpg
 

cadric

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May 3, 2018
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daromer said:
Whats the current you want to be able to trip?

S3N is smaller as example.

The ones you linked are shunt trips for normal breakers. Can you find Breakers large enough? In generall max is 63A only.

Hi daromer,

Yes I used 63A breakers, one for each Inverter.
Just Like you showed in your project page.
 

Crimp Daddy

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From my understanding the shunt trip should go on the battery main feed to the system... you want to be able to remove the battery from the system entirely in a critical fault.

I can see some scenarios where tripping on the inverters breakers could be too far downstream.
 

cadric

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Crimp Daddy said:
From my understanding the shunt trip should go on the battery main feed to the system... you want to be able to remove the battery from the system entirely in a critical fault.

I can see some scenarios where tripping on the inverters breakers could be too far downstream.

OK, that would mean I have to put it directly at the Batteries.
Then I have to rearange the setup.

Thanks for the hint.

Regards

cadric
 

Crimp Daddy

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Yes, I think that would be ideal.

On a side note, if your inverter breakers are sized appropriately, you can still leave those breakers in place in case an inverter has an internal fault or high load condition, but would not need shunt trip capability.

On the flip side, your shunt trip located at the batteries could be a breaker if you can find one sized appropriately, but doesn't have to be used as one. As of right now, I am using mine only to disconnect the batteries in an under voltage condition until my system grows.

Not the most applicable video to you, but I have some recorded content of how I used my ABB shunt trip.

 

daromer

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The shunt trip that the bms should trip is the ones hooked from the batteries. The breakers on the output of the inverter is something else.
 

cadric

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OK, I now see the need for a seperate Unit.
Thank you both for enlighting me.

Regards

cadric
 

OffGridInTheCity

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Yea - the shunt-trip should isolate the battery *completely* which includesthings you don't normally think about such as the charge controllers and power taps - e.g. all electronics that are part of the circuit.
 

daromer

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All electronics except the bms. IF you isolate that One you cant engage again safely since you dont know status :)
 

OffGridInTheCity

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daromer said:
All electronics except the bms. IF you isolate that One you cant engage again safely since you dont know status :)
Interesting... I thought disconnect should include Batrium (for example)- e.g. all electronics. The fact that it tripped means 'manual attention' is required- e.g. go to it physically and inspect and then perhaps turn it back on and see what Batrium (for example) says... If Batrium is still on/hooked to battery it will continue to drain power.

In my design, I'm planning to independently power the Batrium thru a local/nearby laptop USB. This has it's own battery backup - enough for several hours. I use the laptop as VPN/remote desktop portal as well for monitoring. If I don't get to it by then - as in out on vacation for a week - I truly want the entire system to be off.

Of course I'm interested in your perspective as my plans above might sound good to me - but be overkill etc. I know you've spent a LONG TIME on this :)
 

Crimp Daddy

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I think it would be OK to include or exclude the BMS really to a degree it might be personal preference, I can understand the argument both ways.

I think its worth mentioning once it trips, it wont reconnect without physical user intervention. On the ABB you must physically turn the breaker off, then on again to reset the shunt trip breaker. If the fault condition is still active (meaning the shunt trip coil is energized), it would immediately trip again until the condition is cleared.

The system cannot resume by itself regardless of if you decide to kill power to the BMS or not.

The only benefit of keeping the BMS energized is because you want to be able to connect to it for data or to investigate. Perhaps you want to maintain remote connectivity or keep the system on for the purpose of logging. I can certainly understand being ok with the entire system, including the BMS being offline until you have a chance to investigate. Considering most systems are quite large, I suspect the low drain isnt really an issue, Personally Iwould keep the BMS online.
 

daromer

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If you dont have the BMS running how do you plan to check what happened without connecting the battery? It can be the iNverter that is fryed...

You should have enough battery to power batrium for weeks. If you dont have that the battery built is not big enough for your system as a starter.


You should power batrium through the battery and NOT through USB. USB is only for setting it up and nothing else. Batrihm should be directly connected to the battery with only a simple fuse.
 
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I was thinking about powering Batrium from an external power supply. So you can completly disconnect battery and still watch what is going on. Longmons are also powered directly from the cells. Those do not disconnect either!? What do you think about this idea?

For sure this is only possible when youre not offgrid completly. Also maybe not the best idea cause if you don't have grid power from any reason, you don't have the BMS running. Maybe I should think about my idea... :)
 

daromer

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A bms should Always be powered Directly on the battery. You dont want it to get disconnected by the breaker. Therefore it should be powered by itself.

IF you dont have enough battery tonpower it for a couple of days your battery bank is way to small ;)

As you Said you want it to work all the time
 
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You could also use the USB port as UPS system. This is what Batrium said. You can benefit from both possibilities then. Having the load unplugged from the battery to stop drain it and Batrium working all the time.
 

daromer

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Yes but what do you Power batrium with? In My world your battery bank is the big source of power and to be honest IF you dont have enough energy in the battery for a week after the shunt trip tripped you messed Up ;)

There is No need to over complicate things. IF you are concerned add 5 more cells to your pack and your good to go. There should always be some juice left and that is more than enough to power a bms for a very long time.

Question: Do you remove your bms on your other devices you have when you dont use them?
 

Redpacket

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A Batrium system (or other BMS units) typically draw so little power compared to the battery bank size, leaving it connected is not going to do the battery any harm - it's not drawing a few amps like an inverter idling, etc.
If you had a system you left unattended for long periods with no charge source, it might be different? (yes over charge protection should still trip the main breaker via the shunt trip too.)

I have a small separate breaker (10A) direct to the battery for electronics so (as mentioned above) I can still see & log the battery state during fault situations.
 
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